smarm/tests/cluster_conn_lifecycle.rs

//! RFC 010 c6a — connection-actor lifecycle against the manager table.
//!
//! The handshake is bypassed here (c6b wires it): each connection is
//! constructed already-established over a real localhost TCP pair, handed a
//! fabricated `Peer`, and spawned. `spawn_established` registers it with the
//! manager, which takes its handle and monitors it, so the table reflects the
//! connection while it lives and reaps it on any exit path. This proves three
//! things at once: a live connection shows up, a commanded `Disconnect`
//! removes exactly that one, and a peer close (EOF, no command) removes the
//! other.
//!
//! TCP parks the calling actor, so everything runs inside `smarm::run`; the
//! single-threaded runtime is fine because every wait is a cooperative fd park.
#![cfg(feature = "cluster")]

use std::time::Duration;

use smarm::cluster::envelope::NodeMeta;
use smarm::cluster::handshake::Peer;
use smarm::cluster::manager::{Call, Manager, Reply, MANAGER};
use smarm::cluster::spawn_established;
use smarm::cluster::transport::tcp::TcpTransport;
use smarm::cluster::transport::{Conn, FramedConn, Transport};
use smarm::cluster::Timing;
use smarm::gen_server::{self, GenServerBuilder};
use smarm::pg::Incarnation;
use smarm::{run, sleep};

/// A fabricated post-handshake peer identity. Only `node_name` matters to the
/// manager table; the rest is filler until c7 consumes it.
fn peer(name: &str) -> Peer {
    Peer {
        node_name: name.to_string(),
        incarnation: Incarnation::new(1),
        meta: NodeMeta {
            role: "test".to_string(),
            region: "test".to_string(),
        },
    }
}

/// One established transport pair over localhost. Relies on TCP backlog so the
/// sequential dial-then-accept needs no concurrent acceptor (same assumption as
/// the c3 conformance suite).
fn pair(t: &dyn Transport) -> (Box<dyn Conn>, Box<dyn Conn>) {
    let mut l = t.listen("127.0.0.1:0").unwrap();
    let a = t.dial(&l.local_addr()).unwrap();
    let b = l.accept().unwrap();
    (a, b)
}

/// Poll the manager until its peer set matches `expected` (sorted), or fail.
/// The bound is generous against a sub-millisecond real cost.
fn wait_peers(expected: &[&str]) {
    let want: Vec<String> = expected.iter().map(|s| s.to_string()).collect();
    for _ in 0..2000 {
        if let Ok(Reply::Peers(got)) = gen_server::call(MANAGER, Call::Peers) {
            if got == want {
                return;
            }
        }
        sleep(Duration::from_millis(1));
    }
    let got = gen_server::call(MANAGER, Call::Peers);
    panic!("timed out waiting for peers == {want:?}; last = {got:?}");
}

#[test]
fn connection_up_commanded_shutdown_and_eof_all_reflected_in_table() {
    run(|| {
        // The manager, started plainly and reachable at its well-known name.
        // (The supervised subtree in `cluster::start` is permanent by design;
        // a plainly-started manager lets this test terminate cleanly.)
        let mgr = GenServerBuilder::new(Manager::new())
            .named(MANAGER)
            .start()
            .expect("manager name is free");

        let t = TcpTransport;
        let (a1, b1) = pair(&t);
        let (a2, b2) = pair(&t);

        // Manage the `a` ends as peers node-b and node-c; keep the `b` far ends
        // open so neither socket is closed from the far side yet.
        spawn_established(FramedConn::new(a1), peer("node-b"), Timing::default())
            .expect("node-b registers");
        spawn_established(FramedConn::new(a2), peer("node-c"), Timing::default())
            .expect("node-c registers");

        // Up: both connections register and the table shows them.
        wait_peers(&["node-b", "node-c"]);

        // A commanded disconnect reaps exactly its own connection: the
        // manager drops that entry's handle and the actor stops.
        assert!(matches!(
            gen_server::call(
                MANAGER,
                Call::Disconnect {
                    name: "node-b".to_string()
                }
            ),
            Ok(Reply::Disconnected)
        ));
        wait_peers(&["node-c"]);

        // A peer close (EOF) reaps the other with no command at all.
        drop(b2);
        wait_peers(&[]);

        // node-b's far end stayed open until here, so its removal above was the
        // disconnect command and not an EOF.
        drop(b1);

        // All connection actors have exited; stop the manager so `run` returns.
        mgr.shutdown();
    });
}